Method of producing cast shell-projectiles.



1. c. MCLACHLAN.

METHOD 0F PRODUCING CAST SHELL PROJECTILES. APPLICATION FILED JULY al, 191e.

Patented Dec. 3, 1918.

wenn' c. nonacntan, or rononro, curante, caravana.-

i nasceva.

Britain, and resident of the city of Toronto,

county of York, lProvince of Ontario, in the qDominion of Canada, have invented certain new and useful Improvements in Methods of Producing Cast Shell-Projectiles, as de scribed in .the following specification and illustrated in the accompanying drawings, that form part of the same.

This invention relates toa method and apparatus for producing projectiles or shells, and is an improvement upon the invention disclosed in my lprior specification 56,365, iiled October 18th 1915.

Tn projectiles produced with the apparatus of said prior application, it was found that the edges of the annular groove formed in the projectile and adapted to'receive4 thedriving band could ynot be formed sharp and even owing to the quick cooling ofthe metal. It is the principal object of this invention to provide a method and means whereby the said edges maybe made sharp and even, to t snugly to the driving band.

The principal feature of this invention consists in the method of forming the annular groove for the driving band by molding the metal forming the marginal edges of the groove to project beyond themain surface of the body of the projectile 'and subsequently removing the projecting portion.

This and other features of the invention win be described in connection with the drawings and pointed out in the appended f claims.

Referring now to the accompanying 4drawings Figure 1 is a half elevation and longitudinal sectional view of the moldused in casting` the projectile or shell.

ig. 2 is a half elevation and sectional view ofthe upper end of a projectile or shell cast in the mold illustrated by Fig. 1 and showing the ridges at the marginal edges of the annular groove which receives the driving band. l

Fig. 3 is a cross sectional view taken on the line 3 3 of Fig. 1.

Like numerals of reference indicate corresponding parts in each hgure.

Referring to the drawings, it will be seen that the mold comprises a circular base 1 having an axially extending core 2 formed on the upper side thereof and with a cen- Speccation of Letters Patent.

Patented Mec. 3, 11116.,

Application iled Juy 31, 1916. Serial 11o. 112,332.`

trally extendin bore 3. The mold further' comprises ay cy indrical member 4C which is provided at its lower end with a ange 5 which isadapted to be secured to the circular base' 1 and with a seat 6 adapted to receive the core 2, and at its upper end with a flange 5a having a beveled boss 5*. v

The mold still further comprises a pair of substantially semi-cylindrical members 4a whichare provided at their lower ends with a flange 41? having a circular beveled recess 4c which is adapted to be secured to the Hangs td and with the beveled seat A@ adapted to receive the beveled boss 5".

The chill members are provided with ra-v dially extending fins or flanges 7 to aid in the rapid dissipation of theheat of the casting. At their upper ends the members t are formcd'with a circular seat 8 which is adapted to receive the head block 9. This headblock is held in position by means of a fastening ring 10 which-is suitably connected to the members 4:, rhe head block is provided with openings 1 and 12, one of which forms the pouring entrance and the other the gas vent.

A sleeve 1,9 is fitted in the bore 3, anda tubular .perforated core center extends through the sleeve 19-and is rigidly supported in central alinement within the mold extending ribs 18. This dry sand core' is shaped externally rto the exacti inner outline of the projectile or shellV to be cast.

j As clearly shown` in Fig. 1 adjacent the upper end of the interior of the semicylindrical members L? an annular recess 25 is formed. This recess has Haring sides 13 'which are beveled o to meet the inner cylcore 18 having longitudinally extending slots4 18a which forni in the casting longitudinally1 lindrical surface of' the members 4a, thus forming the bevels 13?. This groove is vented by means of the holes 13,

A dry sand core 14; is adapted to be seated in the recess 25 and snugly fits thc bottom and the two sides 13 of said recess. but does not contact with the beveled surfaces 13b. Thus two annular grooves 26 are formed between the said 4,core and the bevels 13". ecause of these grooves 26, ridges 14h will be cast on the projectile at the marginal edges of the annular groove 14a. These circumferentially extending ridges are removed in any suitable manner such as ioyl grinding or machining, so 'that their outer lsurface is Y hush With the outer cylindrical surface of theprojectile. The dotted lines in Fig. 2

Aillustrate rthe form of the projectilev after the ridges 14 have been removed.

'It is obvious that by the above described method and means that even, sharp :indaccurate marginal edges are 'for-med for `the groove 14n. This-is a very important featurey because the driving band is placed in the groove'under pressure and must lit the edges of the groove perfectly.'

rlhe provision of the sand core 2 at the nose end of the shell is an important feature as the metal of the end face is not chilled and is therefore easily machined to tofoi'm a surface of uniform diameter to the Iedges of the groove and forming sharp acute placing in said groove a. dry sand core hav-- ing beveled edges spaced from the beveled edges ofthe groove, then pouring a molten metal into the mold to form the shell, the metal flowing into the spaces formed between the core and the .mold and forming a groove in the shell, and ridges on the outer Wall at the marginal edges of the groove, and finali removing the projecting ridges so as to orm sharp acute angled edges to said groove.

3. A method of producing a cast projectile, consisting in providing a chill mold and a core, and a supplementary sand core arranged at the bottom to form the end of the mold forming the nose end of the shell, thenpouring the metal into the mold to form the shell, the surface at the nose end being formed of softer texture than the remaining portion of the shell through contact with the sand surface of the mold.

J. C. MCLACHLAN. 

